1. Technological Field of the Invention
The present invention relates to a portable timepiece and an electronic device that can be worn while walking, and particularly relates to a wristwatch and electronic device provided with an atomic oscillator for generating a reference clock signal.
2. Description of Relevant Technology
In some electronic timepieces, which are electronic devices, a reference clock signal outputted from a reference oscillator is divided to generate, for example, a 1-Hz signal, and time is measured based on the 1-Hz signal. One known example of this type of electronic timepiece is a VHP (very-high-precision) timepiece that achieves an accuracy that is within plus or minus several tens of seconds per year by using a temperature-compensated crystal oscillator as the reference oscillator (Japanese Examined Patent Application (Kokoku) No. 6-31731, for example).
In recent years, standard oscillators that use an atomic oscillator have been proposed (U.S. Pat. Nos. 6,806,784 and 6,265,945, for example).
However, when the same configuration as a timepiece that uses a conventional crystal oscillator is used in cases in which an atomic oscillator is used as the reference oscillator of an electronic timepiece, problems occur in that the heat from the atomic oscillator (for example, the heat from a heater resulting from maintaining the temperature of the cells, the heat generated by a laser diode, or the like; about 85° C.) causes the material of the gear train mechanism and other driven objects, the lubricating oil for allowing these objects to be driven smoothly, the power-supplying battery, and the like to be adversely affected by the increase in temperature.
Specifically, the elements (lubricating oil, oscillating circuit, drive circuit, battery, and the like) constituting the driven objects of the timepiece (the movement) are more likely to undergo deformation, degradation, a change in characteristics, and other undesirable changes.
Also, problems occur in that power loss increases along with heat generation, and power consumption increases as a result.